This invention is in the field of voltage sensors, and relates more particularly to a high-voltage differential sensor which uses an input attenuator.
High-voltage differential sensors are typically used in circuits such as high-voltage power supply circuits, where it is necessary to sense the voltage difference between two lines, each of which may have a high DC potential and an AC component. In the past, high-voltage differential sensor circuits have typically employed resistive dividers in order to scale down high input voltages to a level that can be safely handled by the voltage sensing circuitry. However, such resistive divider circuits suffer from a number of drawbacks. For example, if large-value resistors are used to minimize power dissipation in the dividers, a significant amount of silicon area must be used to implement the resistors. Alternatively, if smaller-value resistors are used to save space, significant amounts of power will be consumed by the resistive dividers due to the high voltages involved.
Accordingly, it would be desirable to have a high-voltage differential sensor circuit which would avoid the power consumption/area consumption tradeoff inherent in prior-art sensor circuits using resistive dividers. Additionally, it would be desirable to have a sensor circuit which is simple and compact in construction, economical to manufacture, and capable of withstanding high input voltages without breakdown.